you should post this burn log in the Nero discussion forum, you will probably get a quicker response.
Looks like a media problem, Princo. Princo is 3rd class media, fake TDK. You can check for yourself if it is worthy here, http://www.digitalfaq.com/media/dvdmedia.htm or you can dowload DVDInfoPro here, and it will inform you about your media http://www.DVDInfoPro.com Use Quality Media; avoid Memorex-CMC, get the good "stuff": Taiyo Yuden, Sony, Verbatim, Ricoh or other top name products. HTH, Rich